Dell's site indicates that the 1300 can use a Mini-PCI card (which is currently less popular than the CardBus format).

I did some searching and could not find anyone offering a Mini-PCI Firewire card. It appears that this slot is intended primarily for wireless networking cards. There wouldn't be any other way to add Firewire to a laptop either.

Which Firewire device were you hoping to use? Some sort of DV camera, maybe?